Unvanquished is an open-source FPS game featuring team-based strategy and RTS elements, pitting humans against aliens in a futuristic setting.
https://forums.unvanquished.net/
Hey, looking decent! 
There are only two things about proportion that strike me: I'm not entirely sure whether it just looks like this due to the slightly tilted perspective, but the handle seems a bit too short to fit a hand comfortably. Apart from that I'd also make the trigger guard a bit more filigree, it looks quite massive currently.
I totally agree on both points. I'll compare the proportions to some real world examples and adjust accordingly.
The real world example you'll want to look at are variations of the Colt 1911, which were the primary source of inspiration for the Pistol.
Great! I happen to have one of those so that should come in handy.
I still need to cut in the thumb groove on the grip, and model the clip for the bottom of the handle. I lengthened the handle and thinned the trigger guard. I was thinking of thickening the grip pads, but they will probably be covered by the character's hand so I'm not sure if that's necessary. Let me know if there's anything else you would like to change.
Do I need to model the entire ammo clip for a reloading animation?
Yes, you will need to make a clip for it. By the way, I'm seriously impressed with how this is coming out! Viech will give you fuller feedback once he wakes up, but I must say that this really looks great. Can't wait to see your texture job later.
Maybe make the muzzle compensator stripe a bit bigger, in case the edge below it allows that. Apart from that this looks flawless, go on!
Will do. Thanks!
Is it just me or is the diameter of the barrel a bit small?
In would also maybe try to streamline the profile a bit. Looking at it from the business end there are lots of details/contours that look like they would snag on a holster or clothing.
Good work. 
Unfortunately Pongoloid doesn't have the time to continue this model, going to reassign.